We have launched at Bristol into the Floating Harbour. You buy a license at the slipway see www.boatlaunch.co.uk/popup.asp?iconID=42
. You can potter around the centre of Bristol and get onto the Avon via the lock. The lock is one of the largest in the country and then cruise along the Avon River. Its all speed restricted but great fun none the less.
In answer to the other question about running at slow speed, the planning hull design will tend to weave around at slow speed, its not your helming thats at fault. (Well thats what I tell my passangers)